1. Field of the Invention
This invention relates to knife operating devices for sewing machines. More particularly, the invention unifies a needle operating means and a knife operating means into one system, to, thereby, omit the assembling of a separate device for the operation of the knife and to, thus, simplify the structure of the sewing machine.
2. Prior Art
Generally, a sewing machine provided with a knife has a knife operating means in addition to a needle operating means. These needle operating means and knife operating means are formed of racks and links of separate systems connected with respective pulley shafts.
Therefore, the sewing machine having a knife mechanism is complicated in the structure; is troublesome to maintain and service, is large in the volume and is disadvantageous to make small. Also, there are a large number of component parts in making such a machine, and is, therefore, very high in cost and difficulty in manufacture.
In view of such problems as are mentioned above of a sewing machine provided with a knife, the present inventors have invented a novel concrete means for solving various problems caused in relation to such sewing machine by combining a knife operating means with a needle operating means so as to be made one system.